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Christopher Zahner

“What do you want to be when you grow up?” Many kids will say, “Doctor!” Or “Astronaut!” I’m lucky to say that, over the course of my career, I have become something of a mix of both. Before I entered medicine, I took Mechanical Engineering from the University of Florida in 2005. Fascinated by space, I joined NASA’s Spaceflight Operations in Mission Control for the International Space Station, where I played an important role in assisting astronauts to repair critical equipment. I later moved onto pathology, but, during the COVID-19 pandemic – while I was co-inventing a makeshift ventilator – I was approached with a unique opportunity to return to NASA through the IMPACT project. The project is a suite of system engineering tools designed to evaluate risk for human health in spaceflight scenarios – truly a once-in-a-lifetime opportunity. In the world of aerospace medicine, I have the privilege of working among a remarkable community of committed and intelligent individuals. As a clinical pathologist specializing in thrombosis and hemostasis, I was asked to assist in assessing the risk of thrombosis during spaceflight. For much of the last 60 years, it was widely believed that the risk of thrombosis in space was nearly zero. However, my involvement in the IMPACT project and collaboration with NASA revealed a significant shift in this understanding. Evaluating the risk with a sample size of only 11 patients proved to be a tremendous challenge (1). Leveraging my extensive experience in thrombosis, I worked to refine the risk profile. It was a complex endeavor, but our collective expertise and dedication enabled us to make substantial progress that would not have been possible without my clinical pathology experience. Being at the forefront of this important work within the aerospace medicine field has been both exhilarating and immensely fulfilling.


  1. J Pavela et al., “Surveillance for jugular venous thrombosis in astronauts,” Vasc Med, 4, 365 (2022). PMID: 35502899.
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